Process for coating round bodies, in particular elastic cores for tennis balls, withseamless felt



w. SEIDEL 3,025,587 c; ROUND BODIES, IN PARTICULAR ELASTIC NNIS BALLS, WITH SEAMLESS FELT Filed Nov. 5, 1957 March 20, 1962 PROCESS FOR COATIN CORES FOR TE INVENTOR Z/Zz/zer Sez'de] ATTORNEYS United States The methods and devices employed hitherto for coating elastic cores for tennis balls with a seamless felt covering were inconvenient and not suitable for industrial application. Hollow spherical caps were employed in the known fulling devices used hitherto for this purpose and these caps were arranged in pairs, facing each other with their concave sides, and performed circular motions in parallel planes; these motions are called Nitschel-motions. The rubber cores, coated with a layer of adhesive vessel, and after a further layer of fibres or wool fleece had been placed on the cores by hand for fulling, as in the manufacture of felt hats, they were further processed between these spherical caps, when the caps performed also an additional vibratory jerky motion, so as to give the bodies to be fulled a change of direction, in the course of the fulling motion, so that they turned about various axes as the process continued.

These devices are not suitable for an efficient and cheap system of simultaneously manufacturing a large number of balls. In spite of the complicated nature of these fulling installations, the balls manufactured in the installation had to be subjected to a further treatment, in a suitable grinding device, after washing and drying, in order to ensure a uniform diameter.

The present invention relates to a process for covering round bodies with a seamless coating of felt, in particular elastic cores for tennis balls, and a device for carrying it out. According to the invention, this process has the characteristic feature that an undercoating of fibres is arranged on the elastic cores, and an outer coating of a felted layer of fibres of the desired strength is made under pressure on these bodies in a circular-body fulling machine, in a continuous fulling process, the fibres being blown into the machine.

The device suitable for carrying out this process has the characteristic feature that a fulling tongue, which has a cylindrical shape and a fiat on its circumference is elastically suspended in an axial position in a rotating fulling drum, so that the flat has a gradient in the direction of motion of the bodies to be fulled, and that the fulling drum has at least one axial opening at one of its faces for blowing in the hair material used for producing the felted layer.

The elastic round cores made of rubber, synthetic resin or similar elastic material are first provided with a layer of adhesive, such as latex, in order to make them adhesive along their surface. Then fibres of wool, hair, or synthetic substances are placed after a brief preliminary treatment with electrostatic energy on the surface of the round core, which has been coated with adhesive. After the round cores in this way have been coated with an undercoating, they are placed for further treatment in a fulling machine. The covering with a basic layer of fibres on the surface of the elastic cores coated with adhesive can also be done by placing parts of a woollen fleece on them by hand. The fulling machine in which the round cores covered with an undercoating are subjected to the further treatment is shown diagrammatically in the form of one embodiment in the drawing, in which:

FIG. 1 is a side elevational view of the fulling machine, and

FIG. 2 is a top plan view of FIG. 1 broken away and shown in section.

atent O "ice The fulling machine shown here is equipped with a fulling drum 1, which rests on two rolls 2, 3 parallel to the drum axis. The rolls 2 and 3 are supported in bearings 4 of a frame 5 with their journals 2' and 3'. Of these rolls, the roll 3 is driven by a belt 6 through belt pulleys 7 and 8 by the motor 9. In order to ensure that the fulling drum 1 is driven effectively, the rolls 2 and 3 can be coupled together by means of a belt 11 running on belt pulleys 10 on the axes of the rolls 2 and 3.

The fulling drum 1 is provided on each of its faces with an axial opening 12, through which hair and plastic fibre can be blow in. A fulling tongue 13 is arranged inside the fulling drum 1, which is supported by arms 14 on springs 15; the arms 14 pass through openings 12 to the outside. The fulling tongue 13 has the shape of a cylinder with a flat upper surface 16 and is arranged in such a way that the fiat surface has a gradient in the direction of rotation of the bodies to be fulled. The distance between the longitudinal surface of the fulling drum and the cylindrical surface of the fulling tongue corresponds to the diameter of the round cores 17 coated with an undercoating, which are placed for further treatment in the fulling drum. The fulling drum is partly filled with a liquid increasing the adhesion of the bodies and also the efficiency of the fulling process such as soap water, diluted acid or also neutral liquid, which contains in a suspension the hair or fibre required for the formation of the felt.

The driving rolls 2 and 3 for the driving cylinder 1 rotate in the directions indicated by the arrows, while this process is being carried out. The round cores 17 are then rolled along the gap between the cylindrical surfaces of the fulling drum and of the fulling tongue, due to the friction between the bodies and these surfaces, so that they rotate in a direction opposite to that of the fulling drum. After the round cores 17 have passed the cylindrical rolling surface of the fulling tongue 13, they move along the inclined flat surface at the top of the fulling tongue 13, and change their axis of rotation frequently due to mutual contact. While this process is being carried out, the new quantities of hairy or fibrous material, which must be determined from time to time, are blown in through one of the axial openings 12 of the fulling drum. Since the round cores 17 continuously change their rotation axis, the fibres are distributed evenly upon the surfaces of the cores. This felt-forming material adheres partly to the round cores, which pass the fiat surface of the fulling tongue, and whose surface has been Wetted, so as to form a thin layer on these cores, and supplement partly the content of hair and fibre of the fulling liquid.

When the felted layer of hair and fibre fulled on the surface of the round cores during this process has reached the desired thickness, the fulling liquid is caused to run out of the drum and fresh water is run in for washing the balls. Washing is carried out in the rotating drum. The water is renewed frequently, and let off, until the balls are cleaned. The fulling drum can naturally also be employed for drying the balls by blowing hot dry air into the drum. The finished parts are manually removed, and new material for fulling is inserted into the drum through the aperture 12 at the drum faces.

White or coloured fibrous material can be employed for fulling the balls. In order to improve the visibility in darkness and if artificial illumination is employed, and in halls, it may be convenient to provide the fibrous ma terial with fluorescent pigment.

While the invention has been described in details with respect to a now preferred example and embodiment of the invention it will be understood by those: skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended,

therefore, to cover all such changes and modifications in the appended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. A process for making seamless felt coating on balls, especially tennis balls, consisting of blowing fibrous material on the elastic core of the ball during continuous unobstructed movements of the balls to present all sides of the balls to the fibrous material simultaneously with continuous fulling for the making of a felt layer that grows symmetrically from the inner to the outer side during the blowing and while the fulling is applied.

2. A process as in claim 1, where the fibrous material to be coated on the elastic cores of the balls are exposed to a brief preliminary electrostatic treatment.

References Cited in the file of this patent UNITED STATES PATENTS Miller July 8, 1924 Dorogi Sept. 17, 1935 Skehan June 19, 1945 Milner et a1 May 26, 1953 Mottet Sept. 4, 1956 Casse May 17, 1960 FOREIGN PATENTS Australia Jan. 24, 1951 Great Britain Sept. 21, 1933 

1. A PROCESS FOR MAKING SEAMLESS FELT COATING ON BALLS, ESPECIALLY TENNIS BALLS, CONSISTING OF BLOWING FIBROUS MATERIAL ON THE ELASTIC CORE OF THE BALL DURING CONTINUOUS UNOBSTRUCTED MOVEMENTS OF THE BALLS TO PRESENT ALL SIDES OF THE BALLS TO THE FIBROUS MATERIAL SIMULTANEOUSLY WITH CONTINUOUS FULLING FOR THE MAKING OF A FELT LAYER THAT GROWS SYMMETRICALLY FROM THE INNER TO THE OUTER SIDE DURING THE BLOWING AND WHILE THE FULLING IS APPLIED. 